On the Structure and Affinities of Palaeodiscus and Agelacrinus . processus labialis. Towards the proximal end of theexterior surface there is a notch, which is continued distally in thesubstance of the pyramid. This I cannot find represented in recentUrchins. The Linese eminentes py rami dales (Val.) are well structure of the teeth in recent Echinoid has been described bvGiesbrecht. Giesbrecht, from a study of the root end, showed thatthe wings of the tooth arose by the superposition of lamellae, which,as the tooth was examined as it approximated to the mouth, becameintimately con
On the Structure and Affinities of Palaeodiscus and Agelacrinus . processus labialis. Towards the proximal end of theexterior surface there is a notch, which is continued distally in thesubstance of the pyramid. This I cannot find represented in recentUrchins. The Linese eminentes py rami dales (Val.) are well structure of the teeth in recent Echinoid has been described bvGiesbrecht. Giesbrecht, from a study of the root end, showed thatthe wings of the tooth arose by the superposition of lamellae, which,as the tooth was examined as it approximated to the mouth, becameintimately connected by secondary calcification. Loven (11, p. 9)noticed these lamella in the tooth of the very young Echinoid, andalso that these lamellar structures soon disappeared, presumably bysecondary calcifications. The tooth of Paleeodiscus shows embryonic 1904.] Affinities of Palmodiscus and Agelacrimis, 37 features in the distinctness of lamellae througli by far the greaterportion of its substance, and by the absence of secondary calcifications. Text Fig-. 7. «5v.
Size: 1033px × 2418px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectproceed, bookyear1904
